All known natural calcitonin peptides contain an amino acid sequence of 32 amino acids. Salmon calcitonin, for example, has the following formula: ##STR1##
In U.S. Pat Nos. 3,926,938, 4,062,815, 3,929,758, 4,033,940 and 4,217,268 are disclosed improved syntheses of calcitonins including the salmon calcitonin referred to above.
The natural calcitonins include the salmon, eel, bovine, porcine, ovine and human calcitonins. For exemplification of the structures of the various calcitonins, see U.S. Pat. No. 4,422,967, Col. b 3, which is hereby incorporated by reference.